So-called “B-crimps” are e.g. produced with manual crimping pliers of the types CS10, CSV10, CS30, CS100 or table crimping devices CS200 of the applicant. However, it is also possible that the crimping tool is a hydraulically actuated crimping tool or any tool actuated by any type of drive.
German standard DIN EN 60352-2 (Version November 2006) describes plugs in the design of crimping sleeves. These crimping sleeves are designated for being crimped by a B-shaped crimping die. At the end of the crimping process, in a rough first approximation the plug has an outer contour in the shape of a “B”. It is possible that the vertical leg of the “B” has a convex curvature. Furthermore, it is possible that the middle horizontal leg of the “B” at least partially is not present. Accordingly, it is possible that the B-shaped crimping contour in a middle transitional region between the two curved contour regions terminates at a point. The cable is crimped within the “B” for providing a mechanical connection and/or an electrical connection between the plug and the cable.
B-shaped crimping dies are used for a so-called “cable crimping”, wherein the plug is crimped with a stripped cable, or for a so-called “insolation crimping”, wherein the plug is crimped with the insolating sleeve of a cable. To name only some examples for options of plugs to be crimped within the B-shaped crimping die, here D-sub contacts male/female, recepticals and terminals (in some cases with lateral port for a cable), cable shoes with closed crimping sleeve, universal tools for different electronic contacts like D-sub contacts or Fsh.6.3/DFK 2, HD20 contacts, HD22 contacts, Modu IV connectors, Postlock contacts, IEC contacts, MQS contacts, MCP 1.5 K contacts, MCP 2.8 K contacts; MCP 6.3/4.8 K contacts, Micro Power Quadlock 5.2, Mini UMNL, Micro Timer, Junior Power Timer, Standard Power Timer TAB 5.8, ABS contacts, SLK 2.8 contacts, MLK 1.2 contacts, LKS contacts, VKS+ contacts, SFK loop spring contacts, VEK spring contacts, flat connectors, MKR/MKS+ contacts, rsA 2+ contacts, RAM−+ contacts, VKR+ contacts, MDK 4/MDK 5 contacts, RAM machined contacts, DFK 3 contacts, FS 2.8+ contacts, AFK/AFS+ contacts, MDK 3 contacts, DFK 40 contacts, MQS contacts, MCP contacts, RSA 2+, MKR−+, MKS−+, RAM−+ contacts, VKR+ contacts, DFK 4 contacts, flat push-on receptacles and taps without insolation sleeve, 1.5/2.5 pin/socket ELA contacts (each sealed or non-sealed and/or insolated or non-insolated in any shape, design and size) are mentioned. With respect to further examples for plugs, it is referred to the advertising brochure “Tools for Professional Application” of the company WEZAG of 2010. However, it is also possible to use the B-shaped crimping dies for other types of plugs.
A basic representation and description of a B-shaped crimping plug both for a “cable crimping” and an “insulation crimping” can be taken from the Journal “Productronic”, Issue 7, 2007, pages 35-36.
For crimping a plug in a crimping die, it is necessary to apply large crimping forces. These large crimping forces are provided by manual actuation, a hydraulic drive or any other external drive. Despite of the requirement to apply large crimping forces, there are high demands and specifications for the generated outer surface and contour of the plug at the end of the crimping process.
One problem of present crimping dies is that frequently at the end of the crimping process it is not possible to remove the plug from the crimping contour of the crimping die without applying removal forces. The reason for the need for removal forces is that the plug apparently “adheres” to the crimping die. However, the application of removal forces might result in damages of the plug, the cable or of the produces mechanical or electrical connection between the plug and the cable. The adhesion between the plug and the crimping die originates in particular from the following causes:                Crimping die halves for crimping plugs might comprise a crimping contour which during the crimping process contacts the plug both in the direction of the crimping axis and transverse to this direction. Accordingly, the plug is deformed by the die contour in both directions. In particular in cases where the die contour is built with slanted or curved contour regions, the plug is both plastically and elastically crimped and deformed transverse to the crimping axis at a narrowing of the die contour. At the end of the crimping process the plug is “clamped” transverse to the crimping direction within the die contour which is due to the elasticity of the plug. The afore mentioned effect does not occur for contour regions of the die contour having an orientation transverse to the crimping direction. However, the effect is of increasing importance with an increased slope of the contour regions of the die contour in crimping direction.        According to an alternative or cumulative attempt for an explanation of the adhesive effect it has been estimated that micro “toothings” or micro “meshings” are built between the die and the plug during the crimping process. These micro toothings or micro meshings might be the cause of the undesired increased removal forces.        It is also possible that micro weldings are built between the die and the plug.        
For avoiding the above mentioned phenomena, usually lead is used as a base material for the plug or for a surface layer of the plug. Lead serves as a kind of lubricating means for easing the removal. However, the European directive EU 2002/95/EG is directed to a limitation of the use of unhealthful materials in electrical and electronical devices. This European directive aims at the avoidance of the use of heavy metal as lead. According to this European directive, since Jan. 7, 2006 work pieces as the present plugs are not allowed to contain lead.
German patent application DE 10 2009 001 949 A1 of the applicant relates to a simplification of the removal of a work piece (as a fitting for a tube connection, a cable shoe, cable end sleeves, plugs and the like) from a crimping contour of crimping pliers. In the patent application it is proposed to equip the die halves with a certain elasticity. Accordingly, at the end of the crimping process the die is elastically widened, so that the die “breathes”. Due to this breathening effect of the die it is possible that the work piece automatically detaches from the die at the end of the crimping process.
U.S. Pat. No. 5,500,999 A describes prior art wherein the plug contacts a first crimping die half defining the contour of the vertical leg of the B. The second crimping die half defines the curved parts of the B. During the crimping process, the second crimping die half is driven towards the first crimping die half. The second crimping die half comprises a bottom region defining the crimping heart. Additionally, the second crimping die half builds inclined surfaces for introducing the plug when moving into the second crimping die half. The opening angles of the inclined surfaces decrease towards the bottom region of the second crimping die half. U.S. Pat. No. 5,500,999 A complains about the problem that at the end position at the end of the crimping process due to the inclined surfaces different heights of crimped work pieces result in a gap x which is built between the two crimping die halves. The width of the gap x depends on the heights of the crimped work piece. The gap x leads to undesired burrs at the outer surface of the crimped plug. U.S. Pat. No. 5,500,999 A suggests equipping the second crimping die half with four contour parts, namely                the bottom region with the crimping heart,        a transitional region diverging from the bottom region,        a tolerance region with parallel contour parts and        an introducing region.        
In the tolerance region the contour parts have a distance that corresponds to the extension of the first crimping die half transverse to the crimping direction. For work pieces with different heights, the first crimping die half might be located at a plurality of different positions in the tolerance regions at the end of the crimping process without the build-up of any burrs.
Also German patent application DE 197 37 863 A1 discloses a crimping tool with a tolerance region wherein the second crimping die half comprises parallel contour parts having a distance corresponding to the width of the first crimping die half.